Bacterial canker is one of the few serious bacterial diseases. It causes flowering cherry and plum trees to fail gradually and eventually die. The signs are branches dying; foliage with little holes, descibed as ‘shothole’; and gum exuding from the main limbs.

The bacteria is prevalent in winter, and it is most important to prevent injury to these trees in that season. For that reason, pruning is done only in summer. Once affected, there is no remedy. If a single branch has been attacked, it can be removed before the disease progresses to the main limbs and trunk.